This invention is directed to improvements in dispensing apparatus, and in particular to a novel and improved electronic control system for use with a hot water dispensing apparatus.
It is frequently desirable in restaurants, offices and the like to have a ready source of hot water for various beverage brewing and/or cooking purposes, as well as for cleaning purposes. To supply hot water for these and other uses, hot water dispensers have come into increasing use. Typically, such hot water dispensers employ a hot water reservoir in which hot water is heated by an electric resistance heater element. The application of electric current to the heating element is typically controlled by various means responsive to a temperature sensing element in the reservoir to achieve a predetermined dispensing temperature.
While the improvement of the invention may be useful in a variety of applications, the invention will be particularly described in connection with the control of dispensing of hot water from a hot water dispenser of the type primarily intended for use in brewing beverages such as tea, hot chocolate, and the like. Such a hot water dispenser generally includes a thermostat to achieve accurate temperature control of the water for dispensing at a desired temperature. Generally speaking, this thermostat energizes a "ready" indicator lamp when the water has been heated to the desired temperature, or to some predetermined temperature near the desired temperature. Often, such dispensers have utilized a manually operated faucet or spigot to dispense the water. However, the present invention utilizes an electrically operated solenoid-controlled valve to electrically control the dispensing of hot water. Operation of the valve may also be controlled by the thermostat to prevent dispensing when the water is not at the desired temperature.
Preferably the hot water dispenser also has a flow regulator in an input water line for replacing water, as dispensed, at a controlled rate. Accordingly, a presettable timer may be utilized to control the solenoid-operated dispensing valve and this will result in a consistent and controlled volume of dispensed water. Such control is particularly useful when the water is used repetitively in the same recipe, or to repeatedly brew a preselected, constant quantity of beverage. This also permits the user to perform other tasks while the water is being dispensed unattended.
When a batch of water has been dispensed as described, it is automatically replaced with the incoming, unheated water through the above-mentioned flow regulator in the input water line. However, in order to to assure that the dispensed water will always be at or near the desired temperature, the present invention employs further means to prevent the user from dispensing a further batch or quantity of hot water when the brewing apparatus does not contain enough hot water to complete the batch before the temperature drops to an unacceptable level. Thus the dispensing of further water is prevented until the same predetermined amount or batch is again heated to the desired temperature. Only at this point may the solenoid-operated dispensing valve again be activated to dispense a further batch or quantity of hot water.
This feature also prevents dispensing water which is not at the desired temperature following a power failure, or following manual dispensing. The brewing apparatus may include a separate manual dispensing switch for manually operating the solenoid-operated dispensing valve when amounts other than preselected timed dispensing amount or batch size are desired.
It should be recognized in this regard that the use of a thermostat to enable or disable valve operation will not necessarily achieve the foregoing end. For example, before the reservoir has completely refilled with water following a dispensing operation, the thermostat may indeed indicate heating of the partial batch of water to the desired temperature. However, if an attempt were made to dispense a further full batch at this point, at least a portion of the batch would be provided from incoming, unheated water and hence the temperature of the batch would be well below the desired temperature. Accordingly, it is an aim of this invention to assure that at least one complete batch or quantity of water is heated to the desired temperature before initiating dispensing thereof.